How stupid are marine mechanics?

G

greenstreak

New Member
Nov 1, 2008
86
I have been having trouble starting my mercruiser 7.4L mpi. I would have to give it throttle before it would start and stay running. I have ask 4 different mechanics why the engine is doing that. I have had 3 different answers. 1 said to adjust my throttle cable going to trottle body. This guy taught mercruiser school for 11 years. I did and that didn't work. another said it was just normal sometimes for the older big blocks to do that. the other one really had no ideal. Well, I was sitting above my engine compartment thinking what could be wrong. It use to start right up. Finally, it came to me. WOW! the IAC. I took out the IAC and adjusted the worm. I turned it in about 1/2" Put it back in place and turned the key. Started on first revolution of the engine. I shut it off 5 more times and tried starting it. Everytime fired right up without me touching the throttle. Here are all these mechanics and none had enough sense to come up with the answer. I don't even work on engines and I was able to figure it out. Then we have to pay these places huge money to mess around with the engines.:smt021

art
 
I had an older 7.4-454 in my Crownline. It was equipped with a Rocestor 4 barrel carb. It was hard starting as well. My mechanic in which I trusted very much also told me they were hard started as per history. He stated that the 4 barrel carb allowed for the "bowl" or resivor to let the gas evaporate over time and when the boat sat for long period of time it needed to be reprimed.

Mine was indeed that unless it was warm then it started first turn. He instructed me of a sequence of priming the carb with the trottle and choke and it worked almost each time during cold starts. He was definately no idiot.
 
Sounds like you only asked mechanics for advice? It's one thing to ask a mechanic for advice and completely different to have them look at it for money when they can check it out themselves. :huh:
 
So you called 4 mechanics and asked then to fix your boat for free over the phone.........without giving them the chance to diagnose the problem with appropriate test gear and get paid for their time, what did you expect?

Watch some of these guys diagnose and repair a modern engine via laptop and then call them stupid.
 
I had the boat into the one place that looked at it while changing the impeller. they never said anything about the iac. Yeah they knew it was an MPI. WOW! I own a business also. the next time I have a customer call me to ask me a question I guess I will just tell them I don't give out free advice. Heck I have never ran my business that way. I have always tried to help out a customer that had a small problem. This wasn't a serious problem. It was just annoying.
 
I never called anybody over the phone. Like I said the 1 place I took my boat into them. the other guy was a mobil marine mechanic that came out to my boat. He was checking the coolers for being plugged. He kept doing the same thing. Pushing the throttle to start it. He was the one that said the older engines, you had to do that to. I even said to him I thought that was for carb engines and not mpi's. The other guys I stopped into their place. I wasn't expecting someone to give me free advice on how to tear an engine down and rebuild it. I was willing to pay either one of the mechanics that was working on my boat to fix it. The others I just ask them what could be worng when I was in their shop.

I guess you guys have never owned a business. I have learned in the 30 years in business if I help out a potential customer with a small issue then they will come back to me with a bigger problem for me to fix. I happen to be in the home improvement business. I get a lot of people call me for advice. I have gotten a lot of customers in the future because I helped them out with a small issue.

art
 
Last edited:
Not a good mechanic who advocated using the throttle to set idle. The IAC can be exercised with the Rinda EFI tester. Scroll and fire the IAC reset function. If the reset doesn't work, replace it. The tester will also tell what the target idle RPM, the actual RPM, and the IAC setting. Easy to see if the IAC isn't working.

Anyone who works on EFI engines must have one of these things. Otherwise he's just working blindly on many issues.

Best regards,
Frank
 
Last edited:
This is what i love about being a mechanic, "your only as good as the last car you F'ed up". You never hear about the ones that go the extra mile or fix something right the first 1000 times. You could fix 1000 cars to better than new condition then screw one up and your a "horrible mechanic". With the internet things like that can RUIN you.

That being said, something as simple as an MPI set up like that the IAC would be the first place id look for idle speed issues.

Did you actually have them diagnose the problem or was it just a "what do you think it could be" question. My theory is if i have to break out the electronics i should be getting paid for it. If its a regular customer i'll do it cheap or even for free as long as it doesn't burn up alot of time. If its some new guy off the street i'll charge you for it most likely. My Education and tools weren't free.



Since you've re-adjusted the IAC have you had any issues? I should adjust on its own. When you turn the ignition on you should hear it readjust. If it doesn't then that could be your problem.
 
Last edited:
To top off all this it should be said that if you searched the forum for this issue you would find probably a dozen threads of people with MPI's and IAC's that have gone bad, seems to be a pretty common thing and a very easy fix.
 
The 7.4 with MEFI-3 seems to use a different IAC than the smartcraft engines. I've not had any IAC problems, but the smartcraft guys seem to replace them pretty often.
 
Ok guys teach me something...

What is an IAC? I obviously do not work on engines.

John
 
Loneranger said:
Ok guys teach me something...

What is an IAC? I obviously do not work on engines.

John
Click to expand...
Its basically a little plug controled by an electric motor. When the throttle plates are closed the engine needs air to idle. The IAC basically plugs a port that bypasses the throttle plates allowing air into the intake.

Heres a diagram i found on google

0900823d800e5604.jpg
 
Last edited:
Idle Air Controller
 
How stupid are marine mechanics?

Probably about as dumb as home improvement contractors.
 
If you're out in a bar and someone comes up to you and starts asking questions about their problem, that's when you have the right to hand them a card and tell them to call you Monday morning. I am NOT that kind of person. This type of poor customer service has come up before, I think, back on the old SR board. Being nice to just one person can pay big dividends down the line. And even if it couldn't, it's just easier to be nice. There's something called a differential diagnosis, which is a fancy term for list of things that could be causing the problem. I get questions like this ALL the time. What does it hurt to give your "differential" to someone, esp if they're an existing customer and you're already in his bilge. I agree with Greenstreak. Someone should have thought of this as a possible cause for his problem, IF they bothered to give it some thought.
 
I even had one of these go out on a Mitsubishi 3000 GT I once had same symptoms as you describe with your boat.
 
You must log in or register to reply here.

Forum statistics

Threads
113,218
Messages
1,428,808
Members
61,115
Latest member
Gardnersf
Back
Top